1. Field of the Invention
The present invention relates to a new herbicidal composition which is effective for both foliage treatment and soil treatment in agricultural areas such as orchards, upland fields, paddy fields and the like, and also in non-agricultural areas.
2. Description of the Prior Art
In general, it takes relatively less time to cultivate an orchard as compared with the time required for cultivation in other agricultural areas. However, in many cases, the orchard is developed adjacent to a forest and/or a wasteland. In these situations, many weeds are extended from the forest and/or wasteland into the orchard. Accordingly, various weeds, such as annual weeds, e.g., Manna-grass, Barnyard grass, Smartweed, and the like; perennial weeds, e.g., Field horsetail, Culy dock, Cayratia Japonica, Bindweed, and the like, and coppice appear. Some of these weeds grow very high and/or in high multiplication. Some weeds appear in the areas immediately surrounding the trees. The following problems, associated with the yield of the fruit and the control and tending of the operation, are caused by the presence of these weeds:
(1) The control and tending operations are disturbed. PA1 (2) The effects of the wind and sunlight are diminished. PA1 (3) Disease and insect damage are caused and promoted. PA1 (4) The nutritional value of fertilizer is lost. PA1 (5) Water in the soil is used up, causing drought injury. PA1 Compound A: PA1 1,1'-dimethyl-4,4'-bipyridylium dichloride ##STR5## Compound B: 1,1'-dimethyl-4,4'-bipyridylium dibromide PA1 Compound C: PA1 1,1'-ethylene-2,2'-bipyridylium dichloride ##STR6## Compound D: 1,1'-ethylene-2,2'-bipyridylium dibromide. PA1 S-benzyl-N,N-di-n-propylthiolcarbamate PA1 b.p. 123.degree.-125.degree. C./0.015 mm Hg PA1 S-(4-methylbenzyl)-N,N-diethylthiolcarbamate PA1 b.p. 107.degree.-115.degree. C./0.002 mm Hg PA1 S-(4-chlorobenzyl)-N-hexamethyleneiminocarbothiolate PA1 m.p. 53.degree.-55.degree. C. PA1 S-(2-chlorobenzyl)-N,N-diethylthiolcarbamate PA1 b.p. 136.degree.-140.degree. C./0.04-0.05 mm Hg PA1 S-(2.5-dimethylbenzyl)-N,N-dimethylthiolcarbamate PA1 b.p. 130.degree.-140.degree. C./0.012 mm Hg PA1 S-(4-chlorobenzyl)-N,N-diethylthiolcarbamate PA1 b.p. 127.degree.-131.degree. C./0.012 mm Hg
In the conventional methods of inhibition of the weeds, it has been known to apply foliage-treatment type herbicides such as 1,1'-dimethyl-4,4'-bypyridylium dichloride or a mixture of 3,4-dichloropropionanilide and .alpha.-naphthyl N-methylcarbamate in the growing period of the weeds, or to apply soil-treatment type herbicides such as 3-(3,4-dichlorophenyl)-1,1-dimethylurea or 2,4-bis(iso-propylamino)-6-methylthio-1,3,5-triazine, and the like before the weed seedlings appear. When the soil-treatment type herbicides are applied, the active ingredient is translocated in the soil and is absorbed by the roots of the trees, causing phytotoxicity. Also, the herbicidal effect is disadvantageously varied by changing said conditions, such as the water content of the soil. On the other hand, when the foliage-treatment type herbicides are applied, the herbicidal effect is relatively stable and confirmation of its efficacy can easily be made. Retreatments can then be made accordingly. As a result, foliage-treatment type herbicides such as 1,1'-dimethyl-4,4'-bipyridylium dichloride and a mixture of 3,4-dichloropropionanilide and .alpha.-naphthyl N-methylcarbamate have been used primarily. However, when 1,1'-dimethyl-4,4'-bipyridylium dichloride is used, the herbicidal effect against grown weeds is inferior. It is considered that this defect is caused by small translocation of the active ingredient into the bodies of the plants. Only the cells of the weeds in the immediate vicinity of the point of contact of the active ingredient are damaged under conditions of intense irradiation. The translocation of the active ingredient in the weeds is quite slow, causing an inferior effect. The herbicidal effect is also disadvantageously decreased by rain-fall after the application. In such cases, the regrowth of the weeds is rapid, whereby the purpose of the application of the herbicide cannot be attained. Accordingly, sequential applications of the herbicides are necessitated. Consequently, a need continues to exist for an effective herbicide especially for use in an orchard against grown weeds.